The so-called “radio frequency identification (RFID)” technology, i.e., an identification tag using radio frequency, is a communication technology applied to an identification system, so that the identification system can identify a specific object through radio signals and read/write related data from/into the specific object without any mechanical or optical connection between the identification system and the specific object. Generally, an RFID tag comprises an antenna and a chip, wherein the antenna has two functions: one function is to receive an electromagnetic wave transmitted from a reader for driving the chip, and the other function is to generate binary data of 0 and 1 by switching the impedance of the antenna when the RFID tag sends back signals. The chip is connected to input ends of the antenna. The RFID technology can be divided into a passive type, a semi-passive type, and an active type, each type having a different property. In the present invention, the RFID tag described hereinafter is mainly the passive RFID tag, which is a mainstream product in the RFID tag market. The passive RFID tag is not provided with any internal power source, and its chip is driven by an electromagnetic wave received by its antenna, wherein the electromagnetic wave is transmitted by an RFID reader of an identification system. When the RFID tag receives enough signals, data stored in the chip will be transmitted to the RFID reader. The passive RFID tag has a low cost, can operate without any power source, and therefore becomes the mainstream product in the RFID tag market.
The RFID tag has ample applications, as determined mainly by the economic benefits it offers in related fields. Specifically, the applications of the RFID tag include:    (1) anti-counterfeit measures for banknotes and products;    (2) identification cards and pass cards (including tickets);    (3) electronic toll collection systems, such as OCTOPUS cards of Hong Kong and EasyCards of Taiwan;    (4) identification of livestock or wildlife animals; and    (5) patient identification and electronic medical records.
Besides, the applications of the RFID tag further comprise logistics management for carrying out real-time monitoring of all links in a supply chain, including product design; raw material procurement; fabrication, transportation, storage, delivery, sales of semi-finished and finished products; and even product return management and after-sales services, so as to precisely control product-related information such as product types, manufacturers, time of manufacture, locations, colors, sizes, quantities, destinations, receivers and so forth.
Referring now to FIG. 1, wherein a widely used, traditional RFID tag 10 is illustrated, the RFID tag 10 comprises an antenna 20 and a chip 30, both of which are provided on a polyimide substrate 40. The manufacturing method of the RFID tag 10 comprises the steps of: attaching a copper foil 41 to a side surface of the polyimide substrate 40, so as to form a flexible copper-clad laminate; etching the copper foil 41 to form the desired antenna 20; and connecting the chip 30 to input ends 21 of the antenna 20, thereby finishing the RFID tag 10. Before the RFID tag can be used in the logistics management of products, it is necessary to process the packing bags of the products with an additional processing procedure for attaching the RFID tag to an outer surface of the packing bags. As a result, the processing cost of the products is increased, while the exterior design of the packing bags is disadvantageously affected. Even the RFID tag itself may be damaged or peeled off during product processing or transportation due to improper attachment of the RFID tag.
Hence, it is important for related manufacturers to find ways to form RFID tags on packing bags while manufacturing the packing bags, in order to substantially reduce the production cost of the RFID tags, and to manufacture various kinds packing bags formed with the RFID tags without increasing the processing cost, and impairing the exterior design, of the packing bags